Recently, wireless sensor systems in which compact sensors having a sensor function and a wireless function integrated are arranged, and in which the respective wireless sensors are networked are developed. In the wireless sensor system, data detected by the sensor function of each of the wireless sensors is collected by a data center, and the like. Moreover, in the wireless sensor, because the installation environment varies, a power generator is equipped so that the wireless sensor can operate in an environment in which it is difficult to supply power.
Furthermore, in the wireless sensor system, the wireless sensor is mounted on an object such as a motor, engine, and a boiler, for example. An operation state of the object is measured by the sensor function of the wireless sensor, and the result of measurement is collected by the data center through a network.
A power generation method of the power generator installed in the wireless sensor varies according to the installation environment of the wireless sensor, and is, for example, photovoltaic power generation, thermal power generation, vibration power generation, and the like. Furthermore, as a power generator, a power generator that applies more than one power generation method is also known. For example, although it is not a kind to be equipped in the wireless sensors, a power generator that adopts a technique of applying both thermal power generation and vibration power generation in combination has been known as a power generator.
Patent Document 1: Japanese Laid-open Patent Publication No. 2009-240086
Patent Document 2: Japanese Laid-open Patent Publication No. 2001-15823
However, when thermal power generation and vibration power generation are used in combination as a power generation method of a power generator, a thermal generation unit that generates power by thermal conversion and a vibration generation unit that generates power by vibration conversion are set to objects being a heat source and a vibration source, respectively, and therefore, the power generator itself increases in size.